Installed base

Installed base (also install base, install[ed] user base or just user base) is a measure of the number of units of a product or service that are actually in use, especially software or an Internet or computing platform, as opposed to market share, which only reflects sales over a particular period. Although the install base number is often created using the number of units that have been sold within a particular period, it is not necessarily restricted to just systems, as it can also be products in general. Because installed base includes machines that may have been in use for many years, it is usually a higher figure than market share. Many people see it as a more reliable indicator of a platform's popularity.

Installed base is not the same as the total number of units sold at any given moment in time (cumulative sales numbers), since some of those units will typically be out of use because they have broken, gone missing, been made obsolete and/or replaced by newer versions.

See also

• Usage share of operating systems
• Comparison of operating systems

External links

• Web browsers' indications of operating system usage from w3schools.com